The present invention relates to an electrolyte composition for a lead storage battery, which can maintain the performance of a storage battery at low temperature by enhancing the performance and life of a storage battery. It can also be fully charged in a short period of time due to a greater current efficiency. The present invention can extend the life of a storage battery due to its effect of removing white-colored lead sulfate without corrosion at the electrode plates, and may lead to recycling of waste storage batteries ruined by white-colored lead sulfate.
A lead storage battery is a storage battery with the longest history. With the changing times, there have been many improvements on the lead storage batteries, and they are being widely used, such as for automobiles, emergency power supplies, and standardization of electric storage. Currently, lead storage batteries approximately take up a 90% share of the total production market of secondary batteries.
A lead storage battery comprises an anode plate (PbO2), a cathode plate (Pb), and electrolyte. By means of electric discharge, the two electrodes both change into lead sulfate (PbSO4). Lead peroxide (PbO2) at the anode plate is made by electrolytic oxidation of lead or lead oxides. This type of active material is porous and has a large applicable area, which can be easily reacted. At the same time, although it is necessary to prevent a collapse or dropout due to the expansion and contraction of volume by way of charge and discharge, the lead sulfate produced during a discharge deteriorates the performance of active materials at the anode plate, which in turn is the main cause of aging of storage batteries.
In order to solve the aforementioned problems, research for aging suppression has been carried out by means of using improved synthetic materials as active materials at the electrodes. Although there is a method of enhancing aging suppression by improving the characteristics of electrolytes, research into this aspect is rather inadequate.
Korean Patent Publication No. 83-1674 discloses a method of preparing an electrolyte composition, which comprises reducing the amount of sulfuric acid in a lead storage battery and adding magnesium sulfate, aluminum sulfate and ammonium fluoborate thereto. However, it is a mere enhancement by solving the problems of conventional sulfuric-acid electrolytes, and therefore is not currently in practical use. Korean Patent Publication No. 98-127040 discloses an electrolyte composition, which is made by adding compounds such as caustic soda to sulfuric-acid electrolyte. Yet, the actual working of the invention is rather questionable due to the neutralization reaction of caustic soda with sulfuric acid (i.e., the main ingredient).
The objective of the present invention lies in solving the problems as above, or providing an electrolyte composition for a lead storage battery, which enhances the performance and life of a storage battery by excluding sulfuric acid from the conventional sulfuric-acid electrolyte.
The electrolyte composition for a lead storage battery of the present invention comprises 0.5xcx9c1.7 wt % of cobalt sulfate (CoSO4), 40xcx9c50 wt % of magnesium sulfate (MgSO4), 0.2xcx9c0.8 wt % of ammonium chloride (NH4Cl), 15-25 wt % of aluminum chloride (AlCl3), and 0.05xcx9c1.0 wt % of nicotinic acid to 100 parts of distilled water. As for the methods of mixing these compounds, generally known methods in the art can be used.
As for the electrolyte composition of the present invention, the upper limits on the amounts of respective components are set in such a way to achieve maximum current efficiency while the lower limits thereof are limitations for achieving performance efficiency for the electrolyte composition.
A conventional lead storage battery may undergo a drop in performance or explosion during rapid charging. However, a storage battery using the electrolyte composition of the present invention can be fully charged in a short period of time due to a greater current efficiency. The present invention has the effect of removing white-colored lead sulfate (PbSO4) without corrosion at the electrode plates. In other words, it can prevent the occurrence of white-colored lead sulfate, which is one of the major causes for shortening the life of a storage battery. Consequently, the present invention leads to the extension of life of a storage battery and recycling of waste storage batteries ruined by white-colored lead sulfate.
Moreover, the specific gravity of the electrolyte composition of the present invention is 1.15xcx9c1.17, which is lower than that of the conventional sulfuric-acid electrolyte (approximately 1.28). In the case of a storage battery using the electrolyte composition of the present invention weight reduction for a battery may also be possible.
Further, the present invention can be used as a storage battery for electric cars, which can solve the current problems thereof with respect to the life, efficiency, and rapid charging. The present invention can be understood in a more specific manner by means of the embodiments and experimental examples as below. Nonetheless, the embodiments as below are for illustrative purposes only and therefore should not be deemed to limit the scope of protection of the present invention.